1. Field of the Disclosure
The present invention relates to a cooling apparatus for a liquid crystal display device, and more particularly, to a cooling apparatus and method for a liquid crystal display device and a method of manufacturing a liquid crystal display device.
2. Discussion of the Related Art
Until recently, display devices have typically used cathode-ray tubes (CRTs). Presently, many efforts and studies are being made to develop various types of flat panel displays, such as liquid crystal display (LCD) devices, plasma display panels (PDPs), field emission displays, and electro-luminescence displays (ELDs) as a substitute for CRTs. Of these flat panel displays, LCD devices have many advantages such as high resolution, light weight, thin profile, compact size, and low voltage power supply requirements.
In general, an LCD device includes two substrates—an array substrate and a color filter substrate—that are spaced apart and face each other with a liquid crystal material interposed between the two substrates. The two substrates include electrodes that face each other such that a voltage applied between the electrodes induces an electric field across the liquid crystal material. Alignment of the liquid crystal molecules in the liquid crystal material changes in accordance with the intensity of the induced electric field into the direction of the induced electric field, thereby changing the light transmissivity of the LCD device. Thus, the LCD device displays images by varying the intensity of the induced electric field.
The LCD device is manufactured by manufacturing an array substrate which includes thin film transistors (TFTs) and pixel electrodes disposed of on respective pixel regions, manufacturing a color filter substrate which includes a black matrix, a color filter and a common electrode, and interposing a liquid crystal layer between the array substrate and the color filter substrate.
In interposing the liquid crystal layer, making a cell gap of the LCD device and forming a seal pattern may be performed. The seal pattern is hardened in a seal hardening furnace which includes a chamber heated at a predetermined temperature.
However, when the liquid crystal is exposed to the high temperature while hardening the seal pattern, alignment of the liquid crystal molecules is abnormally scattered. This scattering causes point defects at many pixel regions, and thus domain defects occur. To prevent this problem, after hardening the seal pattern, rapid cooling is performed to restore the scattered alignment of the liquid crystal molecules to an initial state. The rapid cooling is performed in a chamber of a cooling apparatus.
FIG. 1 is a view illustrating a cooling apparatus for an LCD device according to the related art.
Referring to FIG. 1, the cooling apparatus according to the related art includes a cooling chamber 10 and a chiller 20.
The cooling chamber 10 includes a stage 11 on which a liquid crystal cell 2 is placed, a cooling coil 13, a fan 15 and an air filter 17. The cooling coil 13 is supplied with air from an air supply line. The air supply line supplies air into the cooling chamber 10, and the cooling coil 13 cools the air. The air pan 15 circulates the cooled air in the cooling chamber 10, and the air filter 17 eliminates alien substances which may be included in the cooled air.
A process of cooling the liquid crystal cell 2 using the cooling chamber 10 is performed as follows. The liquid crystal cell 2 is placed on the stage 11, and then the air supplied from the air supply line is cooled through the cooling coil 13 to generate cooled air. Then, the cooled air is circulated in a direction shown as dashed arrows in FIG. 1 by the fan 15, and the liquid crystal cell 2 is thus cooled.
The cooling coil 13 cools the air using evaporation heat which is generated when a refrigerant using Freon gas is evaporated. However, since Freon gas is fatal, it is desired that the Freon gas is not supplied into the cooling chamber 10. Therefore, chiller 20 is equipped outside the cooling chamber 10.
Chiller 20 includes a refrigerant path 30 and a brine path 40. Along the refrigerant path 30, a compressor 31, a condenser 33 and an expansion valve 35 are equipped. Along the brine path 40, a brine tank 41, a brine pump 43, an evaporator 47 and a circulation pump 45 are equipped.
A high-temperature and high-pressure Freon gas outputted from the compressor 31 is condensed in the condenser 33 to be changed in phase into a high-pressure liquid refrigerant. Then, the condensed liquid refrigerant is expanded in the expansion valve 35 and changed into a low-temperature and low-pressure saturated refrigerant. The low-temperature and low-pressure saturated refrigerant is inputted into the evaporator 47, and at this time, a brine is inputted by the brine pump 43 from the brine tank 41 into the evaporator 47. The saturated refrigerant and the brine exchange their heats in the evaporator 47. The saturated refrigerant is evaporated in the evaporator 47, then inputted into the compressor 31, and then repeatedly circulated along the refrigerant path 30. The brine is inputted into the cooling coil 13 by the circulation pump 45, then inputted to the brine tank 41, and then repeatedly circulated along the brine path 40 and the cooling coil 13.
However, the cooling apparatus according to the related art has following problems. Freon gas destroys the ozone layer and its use is therefore restrained in order to protect the environment.
Moreover, brine path 40 is an additional structure equipped in order to prevent the Freon gas from flowing into the cooling chamber 10, thereby making the structure of the chiller 20 more complicated. Accordingly, an area occupied by the chiller 20 increases and production cost increases.
Moreover, since a cooling wind blows along a direction of one end side to an opposing end side of the liquid crystal cell 2, the cooling capability for the liquid crystal cell 2 is reduced.